How Earth’s Biggest Mass Extinctions Stack Up

image via New Scientist

December 17, 2024, 2:00 PM

• •Scientists have identified at least five major mass extinctions in Earth’s history.
• •The most -lethal of these extinctions, the Permian-Triassic extinction around 252 million years ago, most likely took down more than 90 percent of Earth life at the time.
• •The origins of these extinctions are still being debated, but scientists think that most involved large spates of volcanism.

The five biggest mass extinctions in Earth's history have wiped out more than 70 percent of life on the planet at the time. The most deadly of these events, the Permian-Triassic extinction around 252 million years ago, most likely took down more than 90 percent of Earth life. Scientists think that most of these extinctions were caused by large-scale volcanism, which triggered other changes that led directly to extinctions, such as anoxia, or a lack of oxygen, in the oceans. Studying our geological past can also teach us about the present, says David Bond, a mass extinction expert at the University of Hull in England. “We need to learn lessons from these events and use them to try to understand our potential impending diversity crisis.”

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